Topic 3 Reproduction Flashcards
What is sexual reproduction?
- Involves the production of gametes by meiosis
- A gamete from each parent fuses to form a zygote
- Genetic information from each gamete is mixed so the daughter zygote is unique
What are gametes?
They are haploid sex cells
What is meiosis?
It is a form of cell division involved in the formation of gametes, the chromosome number is halved and it involves two divisions
What must occur prior to meiosis?
Interphase
What happens during prophase of meiosis?
- The chromosome pairs line up along the cell equator
- The pair of chromosomes are separated and move to opposite poles of the cell
- Chromosome number is halved
What happens during metaphase?
- Chromosomes line up along the cell equator
- The chromatids are separated and move to opposite poles of the cell
- Four unique haploid gametes are produced
Why is meiosis important for sexual reproduction? (2)
- It increases genetic variation
- It ensure that the resultant zygote is diploid
What is the advantage of sexual reproduction?
It creates genetic variation, increasing the probability of a species adapting to and surviving environmental changes.
Describe the disadvantages of sexual reproduction (2)
- Two parent cells are required, which makes it difficult in endangered populations
- More time and energy is required so fewer offspring are produced
What is asexual reproduction?
A type of reproduction which involves mitosis that produces genetically identical offspring known as daughter cells
Describe the advantages of asexual reproduction (3)
- Onlyone parent is required
- Lots of offspring can be produced in a short period of time, enabling rapid colonisation of an area
What is the disadvantage of asexual reproduction?
There is no genetic variation (except from random mutations) reducing the probability of a species being able to adapt to environmental change
